Studies On The Technique Of The Dynamic Pressure Damage Of Fully-Mechanized Face Under Room And Pillar Mining Goaf

With the sustainable mining of coal resources,mine fields in different mining areas(such as Shendong)began to mine lower coal seams year by year,the high-strength fully mechanized mining often caused the sudden sudden destability of the roof and the resident pillar in overlying goaf,causing roof dynamic pressure disaster.In view of this situation,we need to put forward relevant theories of roof disasters about prediction and control to solve such disaster.This paper based on the key research item of Shanxi Province(2016GY-161):research on the risk assessment and pre-control technology of the roof of fully mechanized coal seam in the shallow mining area,adopting the 3-1 coal of the Hanjinwan coal mine in Shendong Mining Area,considering the effect of residual Wongawillicoal colums by room and pillar mining method in 2-2 mining on the existing working face,integrated use Theoretical calculatio,Field pressure observation,Comparative analysis,Microseismic monitoring,Numerical simulation to study,obtained the following research results:(1)Through the study of the structure model and its instability characteristics of the overburden in shallow coal seam,analyzed the forming conditions of dynamic pressure disaster on roof,discussed its occurrence mechanism.It is believed that the dynamic pressure of the roof is caused by the fracture and rotary of the key layer above the coal pillar.Considering the different number of key layers for the two coal,analyzed the critical conditions of the coal seam spacing of the shallow coal seam combined with the key stratum theory,which can effectively judge the possibility of dynamic pressure disasters.(2)Through the observation of pressure observation and theoretical calculation,statistically analyzed the roof weighting step and the pressure of the fully mechanized coal mining face under different overburden structures,and analyzed the law of mine pressure,found the differences.The study show that in the Wongawilli strip coal pillar area,the pressure intensity is large,the pressure cycle is short,and prone to top plate dynamic pressure disaster.(3)This paper briefly introduces the current prevention and control measures of the dynamic pressure disaster of the shallow coal seam in the shallow coal seam,analyzing its insufficient,and puts forward the technique of pre-loose blasting pillar technology to control the dynamic pressure disaster of the roof,and elaborates its principle and design,providing a new technical ideas for the prevention and treatment of such disasters.(4)Through the microseismic monitoring and mine pressure monitoring to control the effect of the technique of pre-loose blasting pillar technology,proved that blasting pillar can greatly reduce concentrated stress.After the coal pillar is blasted,the overlying strata is changed from simple yield to complete collapse,and the overburden is sinking.The coal pillars play a supporting role in the overlying strata,and the stress concentration area is transferred to acting on the lower coal seam.The study can not only solve the problem of the pressure of the fully mechanized coal mining face in the Hanjiawan coal mine,but also has important guiding significance for the prevention and control of the dynamic pressure of the roof.